MCM3AP-AS1/miR-101/MYCN正反馈环路增强肝癌糖酵解和放疗抵抗的机制研究

Improving the effect of radiotherapy for hepatocellular carcinoma is a difficult problem to be solved in clinical practice. It was reported that glycolysis plays an important role in tumor radiation resistance, and the imbalance of noncoding RNA expression could affect the radiosensitivity of tumor. In previous experiments, we found that miR-101 could increase the radiosensitivity of hepatocellular carcinoma, and MYCN was a downstream target gene directly regulated by miR-101. MCM3AP-AS1 was highly expressed in hepatocellular carcinoma, and its overexpression could cause the down-regulation of miR-101 and up-regulation of MYCN. Overexpression of MYCN could enhanced the expression of MCM3AP-AS1 in hepatocellular carcinoma cells. This subject will further explore whether MCM3AP-AS1/miR-101/MYCN forms a positive feedback loop in hepatoma cells and its effects on glycolysis and radiation resistance of liver cancer cells on the basis of preliminary studies, then further confirming formation of MCM3AP-AS1/miR-101/MYCN positive feedback loop and its regulation of hepatic glycolysis and radiation resistance in the animal level, finally using hepatocellular carcinoma biopsy samples and related clinical information to analyses the expression and correlation of MCM3AP-AS1, miR-101, MYCN and glycolysis-related genes, and evaluate its effect on the resistance of radiotherapy and prognosis of hepatocellular carcinoma. The aim of this study is to provide new clues for the molecular mechanism of glycolysis and radiation resistance of hepatocellular carcinoma, and to provide new molecular targets and ideas for the individualized radiotherapy of hepatocellular carcinoma.

提高肝癌放疗效果是临床亟待解决的难题。文献报道肿瘤糖酵解在肿瘤放疗抵抗中扮演重要角色，非编码RNA表达失调能影响肿瘤放射敏感性。前期实验我们发现miR-101可增加肝癌的放射敏感性，MYCN是miR-101直接调控的下游靶基因，MCM3AP-AS1在肝癌中高表达且其过表达可引起肝癌细胞中miR-101表达下调、MYCN表达上调，过表达MYCN可上调肝癌细胞中MCM3AP-AS1表达。本课题将在前期研究基础上进一步探讨MCM3AP-AS1/miR-101/MYCN在肝癌细胞中是否形成正反馈环路及对糖酵解和放疗抵抗影响；并在动物水平进一步确证；最后利用肝癌临床组织标本及相关临床信息分析MCM3AP-AS1、miR-101、MYCN及糖酵解相关基因的表达及相关性，并探讨其对肝癌放疗抵抗及预后的影响。本研究力求为肝癌糖酵解及放疗抵抗的分子机制提供新线索，为临床肝癌个体化放疗提供新的分子靶点和思路。

放疗抵抗是肝细胞癌局部放疗失败的主要原因，探索肝癌放疗抵抗机制并寻找解决方案是目前亟待解决的难题。课题组首先从临床出发，探索可能影响肝癌患者IMRT或SBRT放疗局部控制及生存结果的因素，并结合自身数据和SEER数据库建立了预测肝癌患者体外放疗生存期的Nomogram模型。接着，从非编码RNA层面探索肝癌放疗敏感性机制：发现抑制HDAC2表达促进MIR22HG启动子区组蛋白乙酰化，从而上调MIR22HG表达、促进miR-22-5p的产生，最终提高肝癌放疗敏感性；发现肝癌细胞经放射线照射后CAPN10 AS1表达升高，可增加 CAPN10启动子区域组蛋白乙酰化水平，促进其转录从而上调 CAPN10的表达，CAPN10 AS1/CAPN10信号轴促进放射后肝癌细胞的增殖、迁移与侵袭，产生放疗抵抗。此外，在治疗层面，合成了一种新型纳米铂药NP(ArtePt)，可同时实现顺铂介导的化疗与青蒿素通过产生ROS 介导的化动力疗法，实现对肿瘤细胞的联合杀伤；另一方面，其内含碘化合物通过点击反应，消耗细胞内的GSH，增加放射线敏感性，实现增强的化学动力治疗和化疗的联合。综上，我们从基础及临床方面探索了影响肝癌放疗敏感性的相关因素，并通过构建新型纳米药物，克服肿瘤放射线抵抗及肿瘤耐药，为临床肝癌个体化放疗提供了新思路。